Package spark.utils

Class IOUtils

java.lang.Object

spark.utils.IOUtils

public final class IOUtils
extends java.lang.Object

General IO stream manipulation utilities.

This class provides static utility methods for input/output operations.

• closeQuietly - these methods close a stream ignoring nulls and exceptions
• toXxx/read - these methods read data from a stream
• write - these methods write data to a stream
• copy - these methods copy all the data from one stream to another
• contentEquals - these methods compare the content of two streams

The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production.

All the methods in this class that read a stream are buffered internally. This means that there is no cause to use a BufferedInputStream or BufferedReader. The default buffer size of 4K has been shown to be efficient in tests.

Wherever possible, the methods in this class do not flush or close the stream. This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use.

Origin of code: Excalibur.

Version:

$Id: IOUtils.java 481854 2006-12-03 18:30:07Z scolebourne $ Code copied from apache commons io source. Changes made (mostly removal of methods) by Per Wendel.

Field Summary

Fields

Modifier and Type	Field	Description
private static int	DEFAULT_BUFFER_SIZE	The default buffer size to use.
static java.lang.String	LINE_SEPARATOR	The system line separator string.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	IOUtils()

Method Summary

Modifier and Type	Method	Description
static int	copy(java.io.InputStream input, java.io.OutputStream output)	Copies bytes from an InputStream to an OutputStream.
static void	copy(java.io.InputStream input, java.io.Writer output)	Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.
static int	copy(java.io.Reader input, java.io.Writer output)	Copy chars from a Reader to a Writer.
static long	copyLarge(java.io.InputStream input, java.io.OutputStream output)	Copies bytes from a large (over 2GB) InputStream to an OutputStream.
static long	copyLarge(java.io.Reader input, java.io.Writer output)	Copy chars from a large (over 2GB) Reader to a Writer.
static byte[]	toByteArray(java.io.InputStream input)	Get the contents of an InputStream as a ByteArray
static java.lang.String	toString(java.io.InputStream input)	Get the contents of an InputStream as a String using the default character encoding of the platform.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LINE_SEPARATOR

public static final java.lang.String LINE_SEPARATOR

The system line separator string.

DEFAULT_BUFFER_SIZE

private static final int DEFAULT_BUFFER_SIZE

The default buffer size to use.

See Also:

Constant Field Values

Constructor Detail

IOUtils

private IOUtils()

Method Detail

toString

public static java.lang.String toString(java.io.InputStream input)
                                 throws java.io.IOException

Get the contents of an InputStream as a String using the default character encoding of the platform.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

Returns:

the requested String

Throws:

java.lang.NullPointerException - if the input is null

java.io.IOException - if an I/O error occurs

toByteArray

public static byte[] toByteArray(java.io.InputStream input)
                          throws java.io.IOException

Get the contents of an InputStream as a ByteArray

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

Returns:

the byte array

Throws:

java.lang.NullPointerException - if the input is null

java.io.IOException - if an I/O error occurs

copy

public static int copy(java.io.InputStream input,
                       java.io.OutputStream output)
                throws java.io.IOException

Copies bytes from an InputStream to an OutputStream.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

Large streams (over 2GB) will return a bytes copied value of -1 after the copy has completed since the correct number of bytes cannot be returned as an int. For large streams use the copyLarge(InputStream, OutputStream) method.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied, or -1 if > Integer.MAX_VALUE

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

copyLarge

public static long copyLarge(java.io.InputStream input,
                             java.io.OutputStream output)
                      throws java.io.IOException

Copies bytes from a large (over 2GB) InputStream to an OutputStream.

This method uses the provided buffer, so there is no need to use a BufferedInputStream.

Parameters:

input - the InputStream to read from

output - the OutputStream to write to

Returns:

the number of bytes copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 2.2

copy

public static void copy(java.io.InputStream input,
                        java.io.Writer output)
                 throws java.io.IOException

Copy bytes from an InputStream to chars on a Writer using the default character encoding of the platform.

This method buffers the input internally, so there is no need to use a BufferedInputStream.

This method uses InputStreamReader.

Parameters:

input - the InputStream to read from

output - the Writer to write to

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.1

copy

public static int copy(java.io.Reader input,
                       java.io.Writer output)
                throws java.io.IOException

Copy chars from a Reader to a Writer.

This method buffers the input internally, so there is no need to use a BufferedReader.

Large streams (over 2GB) will return a chars copied value of -1 after the copy has completed since the correct number of chars cannot be returned as an int. For large streams use the copyLarge(Reader, Writer) method.

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

java.lang.ArithmeticException - if the character count is too large

Since:

Commons IO 1.1

copyLarge

public static long copyLarge(java.io.Reader input,
                             java.io.Writer output)
                      throws java.io.IOException

Copy chars from a large (over 2GB) Reader to a Writer.

This method buffers the input internally, so there is no need to use a BufferedReader.

Parameters:

input - the Reader to read from

output - the Writer to write to

Returns:

the number of characters copied

Throws:

java.lang.NullPointerException - if the input or output is null

java.io.IOException - if an I/O error occurs

Since:

Commons IO 1.3